Function GUCArrayReset

src/backend/utils/misc/guc.c:11818–11879

* Given a GUC array, delete all settings from it that our permission * level allows: if superuser, delete them all; if regular user, only * those that are PGC_USERSET */

 * those that are PGC_USERSET
 */
ArrayType *
GUCArrayReset(ArrayType *array)
{
	ArrayType  *newarray;
	int			i;
	int			index;

	/* if array is currently null, nothing to do */
	if (!array)
		return NULL;

	/* if we're superuser, we can delete everything, so just do it */
	if (superuser())
		return NULL;

	newarray = NULL;
	index = 1;

	for (i = 1; i <= ARR_DIMS(array)[0]; i++)
	{
		Datum		d;
		char	   *val;
		char	   *eqsgn;
		bool		isnull;

		d = array_ref(array, 1, &i,
					  -1 /* varlenarray */ ,
					  -1 /* TEXT's typlen */ ,
					  false /* TEXT's typbyval */ ,
					  TYPALIGN_INT /* TEXT's typalign */ ,
					  &isnull);
		if (isnull)
			continue;
		val = TextDatumGetCString(d);

		eqsgn = strchr(val, '=');
		*eqsgn = '\0';

		/* skip if we have permission to delete it */
		if (validate_option_array_item(val, NULL, true))
			continue;

		/* else add it to the output array */
		if (newarray)
			newarray = array_set(newarray, 1, &index,
								 d,
								 false,
								 -1 /* varlenarray */ ,
								 -1 /* TEXT's typlen */ ,
								 false /* TEXT's typbyval */ ,
								 TYPALIGN_INT /* TEXT's typalign */ );
		else
			newarray = construct_array(&d, 1,
									   TEXTOID,
									   -1, false, TYPALIGN_INT);

		index++;
		pfree(val);